laplace-torch 0.5

📖 Documentation & API reference

The laplace package facilitates the application of Laplace approximations for entire neural networks, subnetworks of neural networks, or just their last layer. The package enables posterior approximations, marginal-likelihood estimation, and various posterior predictive computations. It includes both weight-space and function-space Laplace approximations.

There is also a corresponding paper, Laplace Redux — Effortless Bayesian Deep Learning, which introduces the library, provides an introduction to the Laplace approximation, reviews its use in deep learning, and empirically demonstrates its versatility and competitiveness. Please consider referring to the paper when using our library:

@inproceedings{laplace2021,
  title={Laplace Redux--Effortless {B}ayesian Deep Learning},
  author={Erik Daxberger and Agustinus Kristiadi and Alexander Immer
          and Runa Eschenhagen and Matthias Bauer and Philipp Hennig},
  booktitle={{N}eur{IPS}},
  year={2021}
}

The code to reproduce the experiments in the paper is also publicly available; it provides examples of how to use our library for predictive uncertainty quantification, model selection, and continual learning.

Installation

To install laplace with pip, run the following:

pip install laplace-torch

To use changes in this repository before they appear in a published release, clone the repository and install it from the checkout:

pip install -e .

The default backend, Curvlinops, is always installed. The ASDL and BackPACK backends are optional extras:

pip install "laplace-torch[asdl]"      # AsdlGGN, AsdlEF, AsdlHessian
pip install "laplace-torch[backpack]"  # BackPackGGN, BackPackEF
pip install "laplace-torch[all]"       # both

Extras can be combined, e.g. pip install "laplace-torch[asdl,backpack]". Curvlinops currently depends on BackPACK, so a plain install still pulls it in.

The old asdfghjkl backend, which LowRankLaplace needs, is not on PyPI. Install it via:

pip install git+https://git@github.com/wiseodd/asdl@asdfghjkl

Simple usage

In the following example, a pre-trained model is loaded, then the Laplace approximation is fit to the training data (using a diagonal Hessian approximation over all parameters), and the prior precision is optimized with cross-validation "gridsearch". After that, the resulting LA is used for prediction with the "probit" predictive for classification.

from laplace import Laplace

# Pre-trained model
model = load_map_model()

# User-specified LA flavor
la = Laplace(model, "classification",
             subset_of_weights="all",
             hessian_structure="diag")
la.fit(train_loader)
la.optimize_prior_precision(
    method="gridsearch",
    pred_type="glm",
    link_approx="probit",
    val_loader=val_loader
)

# User-specified predictive approx.
pred = la(x, pred_type="glm", link_approx="probit")

Contributing

Pull requests are very welcome. Please follow the guidelines in https://aleximmer.github.io/Laplace/devs_guide